Table 3.
Study methodological strengths and limitations.
| No of studies (N = 21) | Prevalence (%) | |
|---|---|---|
| Study methodological strength | ||
| COVID cases lab confirmed (PCR or antibody) | 21 | 100 |
| More than 100 COVID patients | 14 | 66.66 |
| Timing of COVID well specified | 14 | 66.66 |
| Long COVID defined > 3 months | 8 | 38.10 |
| Point in time specific and well defined | 10 | 42.11 |
| Control added | 8 | 31.60 |
| Control group with negative antibody test | 2 | 10.50 |
| Clinical assessment (not self/parent reported) | 7 | 36.84 |
| New symptoms on or after COVID | 6 | 31.58 |
| Specify if persistent symptom or if it is symptoms months after acute COVID | 2 | 9.52 |
| Exclude vaccinated/no vaccinated in sample | 4 | 19.05 |
| Duration (end) of symptoms specified | 3 | 14.29 |
| Validated questionnaires or clinical evaluation for symptoms | 5 | 23.81 |
| Bias | ||
| Low chance of recall bias | 7 | 33.33 |
| Low chance of selection bias | 4 | 19.05 |
| Low chance of misclassification bias | 3 | 14.29 |
| Low chance of nonresponse bias/loss of follow up | 3 | 14.29 |
| Stratifications | ||
| Stratify by severity/only one severity | 4 | 19.05 |
| Stratified by age/only one age group studied | 6 | 28.57 |
| Stratified by preexisting medical conditions | 1 | 4.76 |
| Stratified by sex | 2 | 9.52 |
| Stratify by vaccination status | 0 | 0 |